The Federal Aviation Administration is now putting new safeguards in place to prevent another system failure.

The FAA said earlier this month that a damaged database file appeared to have caused the outage in the safety-alert system that distributes notices to pilots and air controllers. In the aftermath, Transportation Secretary Pete Buttigieg promised a thorough examination to avoid another major failure.

“Our immediate focus is technical — understanding exactly how this happened, why the redundancies and the backups that were build into the system were not able to prevent the level of disruption that we saw,” said Buttigieg.

In a letter to Congress, the FAA says it now requires at least two people to be present during maintenance of the system – one of them must be an FAA manager.